Hello. I have a sdg1025 signal generator with no output on either channel. everything on the screen looks normal, it passes its self-test, according to the service manual all voltages on the board are correct except for TA15 and TA16. The manual says they should be 1.5v (sign wave). Im only have 800mv there is a sign wave but not at 1.5v. Anyone seen this type of problem? Thanks in advance